As shown in FIG. 1, a conventional LCD device generally includes a front frame 1, an LCD panel 2, a middle frame 3, a backlight module 4, a back cover 5 and the like. The backlight module 4 includes an optical film, a light guide panel, a lightbar and the like. Wherein, the front frame 1, the middle frame 3 and the back cover 5 respectively have different functions; the front frame 1 is mainly used for fixing the LCD panel 2 and preventing the LCD panel 2 from escaping, the middle frame 3 is mainly used for bearing the LCD panel 2 and shielding partial backlight module 4 from light leakage, and the back cover 5 is mainly used for bearing the optical film, the light guide panel, the lightbar and the like and ensuring the planeness of the backlight module 4.
The middle frame of the LCD device in the prior art is mainly made of plastic material, and the front frame and the back cover are mainly made of metal material. To reduce cost, partial front frame and back cover are made of plastic material instead of metal material. The back cover is divided into a back frame and a bottom plate, and the back frame and the bottom plate are separately made and then integratedly assembled. When the aforementioned front frame, middle frame and back frame are made of plastic material, the main molding method is integrated injection molding. However, because LCD devices have different sizes, the aforementioned frames need to have different sizes correspondingly. Special dies should be developed for all the frames. Because the dies have the characteristics of non-sharing, long manufacturing cycle and high cost, further reduction of the cost of the aforementioned frames and further shortening of the development cycle of LCD devices are limited, thereby demanding prompt solution.